Catalytic hydrocarbon reformers for converting air and hydrocarbon fuels into molecular hydrogen and carbon monoxide (reformate) as gaseous fuels for use in, for example, solid oxide fuel cells (SOFCs) are well known.
Fuel-air mixture preparation in catalytic reformers is a key factor in fuel efficiency and reformer life. Inhomogeneous mixtures can lead to decreased reforming efficiency and reduced reformer catalyst durability through coke/soot formation on the catalyst and thermal degradation from local hot spots.
Complete and rapid fuel vaporization is a key step to achieving a homogeneous fuel-air mixture. Fuel vaporization is especially challenging under reformer cold-start and warm-up conditions. In prior art technologies, such as vaporization via a preheated air stream, vaporization from a heated reformer surface, or vaporization via “cool flames”, the overall startup time to the beginning of electric generation by the associated fuel cell can be undesirably extended and overall system efficiency can be substantially reduced compared to under steady-state conditions.
What is needed in the art is an improved heat transfer arrangement that provides greater and faster transfer of heat from a catalyst brick to the incoming air and/or fuel stream to cause more rapid and more complete vaporization of fuel earlier in the startup phase of reformer/fuel cell operation.
It is a principal object of the present invention to improve fuel efficiency, to increase catalyst life, and to shorten start-up time in a catalytic hydrocarbon fuel reformer.